• Publications of The Korean Astronomical Society
• /
• v.32 no.1
• /
• pp.97-99
• /
• 2017

Our understanding of dust emission, interaction, and evolution, is evolving. In recent years, electric dipole emission by spinning dust has been suggested to explain the anomalous microwave excess (AME), appearing between 10 and 90 Ghz. The observed frequencies suggest that spinning grains should be on the order of 10nm in size, hinting at polycyclic aromatic hydrocarbon molecules (PAHs). We present data from the AKARI/Infrared Camera (IRC) due to its high sensitivity to the PAH bands. By inspecting the IRC data for a few AME regions, we find a preliminary indication that regions well-fitted by a spinning-dust model have a higher $9{\mu}m$ than $18{\mu}m$ intensity vs. non-spinning-dust regions. Ongoing efforts to improve the analysis by using DustEM and including data from the AKARI Far Infrared Surveyor (FIS), IRAS, and Planck High Frequency Instrument (HFI) are described.

• Journal of The Korean Astronomical Society
• /
• v.31 no.2
• /
• pp.161-171
• /
• 1998

We have mapped about 1.5 square degree regions of Lynds 1299, a well isolated dark cloud in the Outer Galaxy (l = $122^{\circ}$, b = $-7^{\circ}$), in the J = 1- 0 transition of $^{12}CO$ and $^{13}CO$ with the 13.7 m radio telescope at Taeduk Radio Astronomy Observatory (TRAO). We found that there are two velocity components in the molecular emission, at $V_{LSR} = -52 km S^{-1}$ (Cloud A) and -8.8 km $s^{-1}$ (Cloud B), respectively. We have derived physical parameters of two molecular clouds and discussed three different mass estimate techniques. We found that there are large discrepancies between the virial and LTE mass estimates for both clouds. The large virial mass estimate reflects the fact that both are not gravitationally bound. We adopt the mass of $5.6 {\times}10^3 \;M{\bigodot}$ for Cloud A and $1.2{\times}10^3 \;M{\bigodot}$) for Cloud B using conversion factor. Cloud A is found to be associated with a localized star forming site, and its morphology is well matching with that of far-infrared (FIR) dust emission. It shows a clear ring structure with an obvious velocity gradient. We suggest that it may be a remnant cloud from a past episode of massive star formation. Cloud B is found to be unrelated to Cloud A (d = 800 pc) and has no specific velocity structure. The average dust color temperature of the uncontaminated portion of Cloud A is estimated to be 24$\~$27.4 K. The low dust temperature may imply that there is no additional internal heating source within the cloud. The heating of the cloud is probably dominated by the interstellar radiation field except the region directly associated with the new-born B5 star. Overall, the dust properties of Cloud A are similar to those of normal dark cloud even though it does have star forming activity.

• Journal of The Korean Astronomical Society
• /
• v.29 no.spc1
• /
• pp.171-172
• /
• 1996

We present the results of an rocket-borne observation of far-infrared [CII] line at 157.7 ${\mu}m$ from the diffuse inter-stellar medium in the Ursa Major. We also introduce a part of results on the [CII] emission recently obtained by the IRTS, a liquid-helium cooled 15cm telescope onboard the Space Flyer Unit. From the rocket-borne observation we obtained the cooling rate of the diffuse HI gas due to the [CII] line emission, which is $1.3{\pm}0.2 {\times} 10^{-26}$ $ergss^{-1} H^{-1}_{atom}$. We also observed appreciable [CII] emission from the molecular clouds, with average CII/CO intensity ratio of 420. The IRTS observation provided the [CII] line emission distribution over large area of the sky along great circles crossing the Galactic plane at I = $50^{\circ}$ and I = $230^{\circ}$. We found two components in their intensity distributions, one concentrates on the Galactic plane and the another extends over at least $20^{\circ}$ in Galactic latitude. We ascribe one component to the emission from the Galactic disk, and the another one to the emission from the local interstellar gas. The [CII] cooling rate of the latter component is $5.6 {\pm} 2.2 {\times}10$.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.42 no.4
• /
• pp.258-263
• /
• 2022

This experiment was conducted to confirm the possibility of manufacturing artificial Italian ryegrass hay using far-infrared rays in Korea. The machine used in this experiment was a far-infrared ray dryer capable of adjusting temperature, airflow, and far-infrared radiation, and was conducted on Italian ryegrass harvested in May. Conditions for drying were performed by selecting a total of nine conditions, and each condition was set to emission rate of 42 to 45%, and the internal temperature was set to 65℃. The speed of the air flow in the machine was 40-60 m/s, and the overall drying time was 30 minutes for 42% radiation, 25 minutes for 43% radiation, and 20 minutes for 45% radiation. The final dry matter content according to each drying condition was 88.5% on average, and the dry matter content suitable for hay was shown in the all treatment. Looking at the power consumption according to the drying conditions, the lowest was found in the treatment that dried for 20 minutes at 45% radiation. In the drying rate, there was no difference in drying conditions 1 to 5, but a significantly low tendency was shown in conditions 6 to 7. In terms of feed value, CP and IVDMD were higher than raw materials in most drying conditions, and ADF and NDF contents were low, and tended to be high in drying conditions 4, 7, and 8. Through the above results, it was judged that drying conditions 7 and 8 were the most advantageous when considering drying speed, power consumption, and quality.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.11 no.6
• /
• pp.111-117
• /
• 2002

The high quality and a nearly stoichometric growth of $Cd_{1-y} Zn_y$/Te(y＝0.04) epilayers have been successfully grown on GaAs substrate by hot wall epitaxy (HWE) by optimizing the growth condition including the preheating treatment and Cd reservoir temperature. The relationship between quality and thickness was examined and best value of FWHM from X-ray rocking curve of 121 arcsec are obtained. Also, emission peaks related to the recombination of free excitons such as the ground state and the first excited state were observed in the PL spectrum at 4.2K. The ($A^0$, X) emission related to Cd vacancy and deep level emission was not measured. These results indicated that the grown CZT/GaAs epilayer was high qualify and purity.

• The Bulletin of The Korean Astronomical Society
• /
• v.28 no.2
• /
• pp.30-30
• /
• 2003

• The Bulletin of The Korean Astronomical Society
• /
• v.36 no.2
• /
• pp.115.2-115.2
• /
• 2011

UWISH2 (UKIRT Widefield Infrared Survey for $H_2$) is an unbiased, narrow-band imaging survey of the Galactic plane in the $H_2$ 1-0 S(1) emission line at $2.122{\mu}m$ using the Wide-Field Camera (WFCAM) at the United Kingdom Infrared Telescope (UKIRT). The survey covers about 150 square degrees of the first Galactic quadrant ($10^{\circ}$ < l < $65^{\circ}$; $-1.3^{\circ}$ < b < $+1.3^{\circ}$). The images have a $5{\sigma}$ detection limit of point sources of K~18 mag and the surface brightness limit is $10^{-19}\;W\;m^{-2}$ $arcsec^{-2}$. The survey operation began on 28 July 2009 and has completed on 17 August 2011. We have been studying the supernova remnants (SNRs) in the UWISH2 survey area. Among the known 274 Galactic SNRs, the survey area includes 65 SNRs or 24 percent of the known SNRs. The wide-field and high-quality UWISH2 images allow us to identify both the diffuse extended and compact $H_2$ emission associated with SNRs, which is useful for understanding their physical environment and evolution. The continuum is subtracted from the narrow-band $H_2$ images using the K-band continuum images obtained as part of the UKIDSS GPS (UKIRT Infrared Deep Sky Survey of the Galactic Plane). So far, we have inspected 42 SNRs, and found distinct H2 emission in 14 SNRs. The detection rate is 33%. Some of the SNRs show bright, complex, and interesting structures that have never been reported in previous studies. In this report, we present our identification scheme and preliminary results.

• Publications of The Korean Astronomical Society
• /
• v.32 no.1
• /
• pp.175-177
• /
• 2017

In order to reveal physical conditions of molecular gas in active galaxies (active galaxies mean both starbursts and AGNs in this paper), we carried out systematic observations (R = 19 ~ 120) of CO fundamental band at $4.7{\mu}m$ in absorption with AKARI. We also made follow-up CO absorption observations at higher spectral resolution (R = 5000 ~ 1000) with Subaru. Recently, Herschel made extensive observations of highly-excited CO lines in emission in the far-infrared. The two data sets (absorption and emission) sometimes provide us with apparently inconsistent results. One case is starburst galaxies: Subaru observations showed low temperature of molecular gas toward the starburst NGC 253, while Herschel detected highly excited CO lines in the starburst. This suggests that warm molecular clouds are more deeply embedded than newly formed star clusters. The other case is obscured AGNs; Herschel detected highly excited CO lines in emission in nearby AGNs, while AKARI and Subaru observations showed CO absorption only in some of the obscured AGNs. This could reflect the difference of nature of molecular tori in these AGNs. We propose the combination of the absorption and emission observations as an effective tool to reveal geometry of warm molecular clouds in active galaxies.

• Publications of The Korean Astronomical Society
• /
• v.27 no.4
• /
• pp.305-310
• /
• 2012

AKARI's all-sky survey resolves the far-infrared emission in many thousands of nearby galaxies, providing essential local benchmarks against which the evolution of high-redshift populations can be measured. This review presents some recent results in the resolved galaxy populations, covering some well-known nearby targets, as well as samples from major legacy surveys such as the Herschel Reference Survey and the JCMT Nearby Galaxies Survey. This review also discusses the prospects for higher redshifts surveys, including strong gravitational lens clusters and the AKARI NEP field.

• Bulletin of the Korean Chemical Society
• /
• v.20 no.4
• /
• pp.436-440
• /
• 1999

The highly resolved absorption spectra of mer-[Cr(dpt)(Gly-Gly)]ClO4·H2O [dpt = di(3-aminopropyl)amine, H2Gly-Gly = glycylglycine] have been measured between 13000 cm-1 and 50000 cm-1 temperatures down to 2 K. The vibrational intervals were extracted by recording emission and far-infrared spectra. The characteristic infrared bands in meridional isomer were discussed. The four-teen electronic origins due to spin-allowed and spin-forbidden transitions were assigned. With the use of this electronic transitions, a ligand field optimization based on the exact known ligand geometry have been performed to determine more detailed bonding properties of Gly-Gly and dpt ligands. It is confirmed that the peptide nitrogen of the Gly-Gly has a weak π-donor property toward chrornium(Ⅲ) ion.